It is known that oxide surfaces can be treated with organosilicon compounds in order to improve the bond between the oxide filler and organic polymers with various chemical compositions and thereby to improve the reinforcing properties of the fillers in the polymers.
To this end, for example, the organosilicon compound in question can be dissolved in an organic solvent and e.g. then used to treat clays (U.S. Pat. No. 3,227,675 --Huber).
U.S. Pat. No. 3,567,680 teaches the modification of kaolines suspended in water with mercapto and amino silanes. However, those organosilicon compounds are water-soluble in the amounts necessary for the modification, so that, even in this instance, the treatment of the filler uses a solution.
U.S. Pat. No. 4,151,154 relates to silicate fillers whose surface is exposed to a treatment with two types of organosilicon compounds.
The oxide particles are treated in such a manner that they exhibit a rather strong affinity for water and to improve the ease of distributing them in aqueous systems.
U.S. Pat. No. 4,076,550 teaches the use of sulfur-containing organosilicon compounds in vulcanizable rubber mixtures.
These compounds can also be used in mixtures with silicas which, however, are not pretreated thermally and exhibit only a limited storage stability.
EP-PS 0 126 871 describes a method in which the surfaces of silicate fillers are modified with the aid of an aqueous emulsion of organosilicon compounds which are insoluble in water.
U.S. Pat. No. 4,141,751 is concerned with a method which does not require a solvent but is not practicable for certain organosilicon compounds, as experience demonstrates.